Thai - New Air Injection Technology For Heavy Oil Recovery And In Situ Upgrading

Gréaves, M.; El-Sakr, A.; Xia, Tian; Ayasse, Conrad; Turta, Alex

doi:10.2118/99-15

Cited by 23 publications

(13 citation statements)

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“…All of these tests were sustained in a HTO mode, with peak temperatures greater than 390˚ C (medium oil) or 450˚ C (heavy oil) (9)(10)(11) . This is convincing evidence that the THAI process is able to sustain combustion in an HTO mode.…”

Section: Introductionmentioning

confidence: 99%

Upgrading Athabasca Tar Sand Using Toe-to-Heel Air Injection

Xia

Gréaves

2002

Journal of Canadian Petroleum Technology

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The unique operation of the THAI (Toe-to-Heel Air Injection) process, enables very high oil recovery and substantial in situ upgrading. Both thermal upgrading (non-catalytic) and also catalytic upgrading, in which a catalyst is emplaced along the horizontal producer well, were investigated. 3D physical model experiments were conducted on virgin Athabasca tar sand bitumen to investigate dry and wet combustion performance. These results were compared against those from a steamflood test, which was subsequently followed by air injection. Excellent ignition, very stable combustion propagation and thermal upgrading of nearly 10 ° API were achieved using Athabasca tar sand. Additional upgrading was achieved using an in situ catalyst. THAI has the extra advantage that some hydrogen is generated in situ, providing further significant upgrading via hydroconversion. There are also substantial environmental benefits because of the large reductions in sulphur and heavy metals in the produced oil. Furthermore, oil is produced without "displacement delay," immediately ahead of the combustion front. The oil recovery using THAI was greater than 75% OOIP. Introduction The world's conventional crude oil production is expected to reach its peak in the second decade of this century and enter a permanent decline phase(1). The composition of the oil barrel is getting heavier, and diluent blending "stop-gaps," assisted by very limited coker upgrading capacity will, eventually, be insufficient to cope with the increasing demand for light oil. Historically, heavy oil trades at a substantial discount to that of premium light crude oil. Therefore, it has lower economic value and also market potential, unless new technology is developed to upgrade it to lighter oil, in an economic manner. The Athabasca Tar Sand deposit of northeastern Alberta, Canada, is one of the largest reserves of bitumen in the world. These are estimated to be 212.9 ??109 m3 (1,339 ?109 bbl)(2). Although about 10% of the bitumen reserves are mineable, the rest of the Athabasca Tar Sands have to be exploited by in situ recovery technology. A number of in situ oil recovery methods, such as steam assisted gravity drainage (SAGD)(3) and in situ combustion (ISC)(4, 5), have been extensively studied, both in the laboratory and in field tests. In situ combustion (ISC) is a thermal EOR method, in which a small fraction of the oil (or coke) in the oil layer is burned in order to mobilize the unburned fraction. Due to the strong exothermic oxidation reactions between hydrocarbon (or coke) and oxygen, the temperature of the oil-bearing matrix in the combustion zone is 500 to 700 °C, which is much higher than in steam flood processes (150 to 250 °C). High temperatures are very favourable for tar sands and heavy oil reservoirs, because not only is the oil viscosity reduced by several orders of magnitude, but the heavy residue is also thermally cracked to lighter compounds.

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Section: Introductionmentioning

confidence: 99%

Upgrading Athabasca Tar Sand Using Toe-to-Heel Air Injection

Xia

Gréaves

2002

Journal of Canadian Petroleum Technology

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“…The way in which the mobile oil zone operates is also responsible for preserving downhole upgrading, since oil is immediately produced via the open section of the horizontal producer well, instead of being displaced into the downstream oil layer. Details of THAI are given by Greaves et al (1)(2)(3) .…”

Section: Introductionmentioning

confidence: 99%

CAPRI-Downhole Catalytic Process for Upgrading Heavy Oil: Produced Oil Properties and Composition

Gréaves¹,

Xia²

2001

Canadian International Petroleum Conference

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“…The experiments were carried out in a low pressure, rectangular combustion cell, measuring 0.4 m x 0.4 m x 0.1 m. Detailed descriptions of the equipment and procedure have been given in previous papers (9,10) .…”

Section: -D Physical Model Experimentsmentioning

confidence: 99%

“…There are no published numerical modelling studies of the THAI process -'Toe-to-Heel' Air Injection, described recently by Greaves et al (9,10) . This new air injection process achieves very stable combustion performance by controlling adverse gas override.…”

Section: Introductionmentioning

confidence: 99%

Simulation Studies of THAI Process

Gréaves¹,

Xia²

2000

Canadian International Petroleum Conference

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A preliminary numerical simulation study of THAI -'Toe-to-Heel' Air Injection, is described. The reference physical model experiments are one dry and one wet combustion test carried out using heavy Wolf Lake Oil. The experiments operated in a completely stable manner and it was of primary interest to investigate via the numerical model, whether this behaviour could be predicted. The experiments were three-dimensional and so a corresponding 3-D numerical model was constructed using the STARS reservoir simulator. Initially, because of insufficient fuel laydown in the path from the injector well to the horizontal producer well, the predicted result was unstable because of oxygen breakthrough into the toe of the horizontal well. Using a sleeve-back modification to the horizontal well gave a stable result for dry combustion. Sleeve-back was also used to initiate the wet combustion simulation, but it was then removed and the combustion front propagation continued in a stable manner. A third component -coke was added to the oil pseudo-component description in a further simulation of the dry combustion experiment. This was set equal to the measured coke residue in the gas swept zone in the sandpack. The simulation result was completely stable, implying that an improved cracking reaction model was needed in the numerical model. The 3-D simulation result predicts a very stable combustion front profile, which propagated stably and completely to the end of the sandpack. Overall oil production was 85% OOIP, which was in good agreement with the experimental results.

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Thai - New Air Injection Technology For Heavy Oil Recovery And In Situ Upgrading

Cited by 23 publications

References 1 publication

Upgrading Athabasca Tar Sand Using Toe-to-Heel Air Injection

Upgrading Athabasca Tar Sand Using Toe-to-Heel Air Injection

CAPRI-Downhole Catalytic Process for Upgrading Heavy Oil: Produced Oil Properties and Composition

Simulation Studies of THAI Process

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